Month: September 2016

Posted on

Harmonic tremor change close to Grímsfjall volcano

There seems to be a harmonic tremor pulse or a change around Grímsfjall volcano. This might be nothing, but the change appears on several SIL stations around Vatnajökull glacier. The harmonic tremor is strongest on Húsbóndi SIL station and Jökulheimar SIL station. This might be something else then magma, glacier movement or sudden flood are an possibility.

hus.05.09.2016.at.01.29.utc
Húsbóndi SIL station. Copyright of this image belongs to Icelandic Met Office.

jok.05.09.2016.at.01.29.utc
Jökulheimar SIL station. Copyright of this image belongs to Icelandic Met Office.

Currently I don’t know what is creating this change in harmonic tremor. I know it is not weather and this is on too many SIL station to be local noise. The SIL station at Grímsfjall volcano doesn’t show any change, so everything is quiet in that volcano. But this is within Grímsfjall volcano fissure swarm that contains the volcano Þórðarhyrna, it last erupted in the year 1902 and has been quiet since (information about eruptions in Þórðarhyrna volcano can be found under Grímsfjall volcano eruption history).

If anything happens I’ll update this article or post a new one.

Posted on

Earthquake activity in Bárðarbunga volcano 2-September-2016

On 02-September-2016 two earthquakes with the magnitude 3,3 and 3,5 took place in Bárðarbunga volcano. The magnitude was 3,3 for the earlier earthquake and 3,5 for the second earthquake.

160903_1705
The earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.

This type of earthquake activity is so common now in Bárðarbunga volcano that I rarely bother now to write about it. This type of earthquakes now happen once to twice in Bárðarbunga volcano each week. The reason for this earthquake activity are stress changes in the caldera. This is I suspect going to take a long time, I’m looking at years of this type of earthquake activity in Bárðarbunga. What also makes this more complicated is the rifting currently taking place inside the volcano and on nearby fissures. The results of this mixture might get interesting in the future.